The present invention relates to a collapsible container for purposes of storing and transporting large quantities of liquid and solid materials. The transportation system in the United States and throughout the world is heavily overloaded with the transporting of various types of cargo by road, rail, sea and air. Such movement of goods has long been dependent upon the type of containers used to carry the materials. An important problem which always accompanies the transporting of cargo is the storage and return of the empty cargo containers to the origin site for purposes of refilling and re-use. As a result of this problem much investigation has been done over the years to improve such containers to maximize their efficiency and improve utilization of warehouse and transportation space.
The earliest major transporting and storage device was the barrel or large tank. These devices were generally made of wood and metal materials. With the advent of high strength plastic materials, molded containers became a welcome addition in the container industry. As plastic containers are less expensive than the containers previously used, they are often considered disposable items which can be eliminated upon being emptied.
A recent breakthrough in the transporting of cargo is the mass containerization used primarily in transporting cargo in great volume. However, there is little advantage in using this technique in moving smaller quantities of cargo than can fill a large shipping container such as the size of a railroad freight car. Moreover, even the large, self-contained vessel comprises smaller receptacles which again are either disposable or must be reshipped for refilling.
The present invention is directed to a container which is collapsible when empty for ease of storage when not in use and for efficient retransporting to the origin site for refilling. Although it is collapsible, it is of high strength and can support and contain large quantities of heavy, cumbersome materials. Moreover, the collapsible container of the present invention has been specially adapted with various features which render it particularly efficient and reliable in the transporting and storage of materials.
Collapsible containers have heretofore been the subject of much investigation for various end uses. For example, in U.S. Pat. No. 2,767,757 issued to Marder, a collapsible container with supporting frame is described which is adapted for use as a laundry hamper, wastebasket or like container. This receptacle is not adapted for supporting large and heavy quantities of materials nor does it have means for completely enclosing or sealing its contents. It is not designed for withstanding the abuse which would be incident to its use as a shipping container. The collapsible bag is formed of a flexible fabric material but is only attached to the frame at the top. Such a construction does not relate to the collapsible container of the present invention.
Other devices have been suggested and described which have the ability to be collapsed or reduced in size when empty yet be used for storing and transporting materials. U.S. Pat. No. 2,837,860 issued to Norling, describes a collapsible bucket which comprises a tight canvas bag having a circular bottom reinforced by a galvanized steel ring. Again, this type of a construction does not lend itself to withstand handling during transportation nor in fact was it intended for such use as is clear from the flexible bag which is of a water permeable canvas material.
It has been suggested to use a collapsible container which comprises a flexible fabric material in the transporting and storage of large quantities of materials including liquid cargo. However, when such a container has been suggested, it has required a very sophisticated and complicated construction in the supporting metal frames to enable it to carry and hold with relatively heavy and cumbersome materials. This may be illustrated in U.S. Pat. No. 2,623,565 issued to Unthank. The collapsible tank in the Unthank patent is described as suitable for transporting liquid cargo in bulk. The tank walls are of a flexible material such as a fabric-reinforced, liquid-proof material which forms sidewalls which are capable of being folded into a plurality of superimposed pleats upon being collapsed. The material is anchored to the frame at the outer fold of each of the pleats.
Of particular significance in the tank described in the Unthank patent is that the tank has not been designed for easy transporting as, for example, the tank is designed to be at least temporarily and probably permanently secured to or fixed to the floor of a ship wherein the tanks are transported. Moreover, the frame of the tank has a very costly and intricate construction which is necessary for the method in which that tank collapses. For example, the tank of Unthank comprises some nine or more steel tubes with intricate linking plates, hinges, collars and clamping plates to enable the fabric sidewalls to fold at the pleats, to follow the contour of the linking plates upon being collapsed. The device of Unthank is not believed designed for handling in transporting. Also, if a defect occurs in the bag because of the intricate means of attachment to the supporting frame, it would be a costly component to replace.
Still another suggestion for a collapsible transporting device is that described in U.S. Pat. No. 1,507,977 issued to Schaefer. This patent merely describes a bag which is suspended within a collapsible crate. This shipping crate specifically is adapted for transporting perishable fruit where the bag is utilized for protection of the fruit and not as the primary containing means.